JP2008249713A - Battery pack, semiconductor device, and portable device having built-in battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery pack capable of accurately performing residue prediction of a secondary battery and charge of the secondary battery while reducing the cost. <P>SOLUTION: Secondary batteries 14a-14c in the battery pack 12 to be connected with a portable device is charged by a battery charger 22 built in the portable device 11. The battery charger 22 performs constant voltage and constant current control during charging based on a measurement result of charging current and charging voltage supplied from an external power and measurement result from a measuring means in the battery pack for measuring current flowing into the secondary battery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a battery pack, a semiconductor device, and a portable device incorporating the battery pack.
In general, lithium ion batteries, which are secondary batteries, are widely used for batteries of portable electronic devices such as notebook computers. Lithium ion batteries have advantages such as a low operating cost of equipment on which they are mounted and a large current capacity that enables instantaneous discharge. Usually, a device equipped with a secondary battery such as a lithium ion battery has a built-in charging circuit for charging the secondary battery by connecting an external power source such as an AC adapter. By the way, in recent years, portable devices have been improved in performance and miniaturization, and while charging the rechargeable battery to full charge at the time of charging while reducing the area of the built-in charging circuit. Is required. In general, portable devices have a remaining amount prediction function that predicts the remaining amount of secondary batteries and notifies the user of the battery consumption state when using the device in order to avoid troubles such as data loss. Is provided. For this reason, it is necessary to accurately predict the remaining amount of the built-in secondary battery.

FIG. 11 is a block diagram illustrating a general schematic configuration example of a portable electronic device such as a notebook computer equipped with a secondary battery.
A portable electronic device (hereinafter referred to as a portable device) 101 is connected to a plurality (two in the figure) of secondary batteries 102a and 102b such as lithium ion batteries incorporated in the battery pack 102, and each secondary battery 102a, It operates with power supplied from 102b. The portable device 101 also operates by receiving power from the AC adapter 103 by connecting to an external power source such as the AC adapter 103.

  The schematic configuration of the power supply device of the portable device 101 will be described. The portable device 101 includes a power supply microcomputer 104, a charger 105, a selection circuit 108, first and second DC-DC converters 109 and 110, and a switching regulator. Of LDO111.

  The charger 105 is connected to the battery pack 102 and the AC adapter 103, supplies a charging voltage and a charging current to the secondary batteries 102a and 102b based on a control signal from the power supply microcomputer 104, and performs constant voltage / constant current charging. Do.

  The selection circuit 108 selects at least one from the battery pack 102 (secondary batteries 102a and 102b) and the AC adapter 103, and inputs the input voltage supplied from the selected power source to the first and second DC-DC converters. 109 and 110 and the LDO 111.

  The first DC-DC converter 109 generates a power supply voltage to be supplied to, for example, a CPU (not shown) based on this input voltage, and the second DC-DC converter 110 is a peripheral circuit (not shown). A power supply voltage is generated to supply to The LDO 111 generates a power supply voltage for generating a clock signal (not shown) based on the input voltage.

In recent years, portable devices 101 equipped with such secondary batteries 102a and 102b are generally provided with a remaining capacity predicting function for notifying a user who uses the secondary battery 102a and 102b of the remaining battery capacity.
The remaining capacity prediction function will be described in detail. Lithium ion batteries are vulnerable to overdischarge, and if the user accidentally overdischarges, the function of the battery may become unrecoverable even if charged. Therefore, in order to prevent such overdischarge, the battery pack 102 includes a protection circuit 112 that detects that one of the secondary batteries 102a and 102b has become equal to or lower than a specified voltage and stops discharge. Built in. When the protection circuit 112 is activated, power supply from the secondary batteries 102a and 102b to the portable device 101 is cut off, and the portable device 101 stops operating. At this time, particularly in the portable device 101 such as a notebook personal computer, there is a possibility that data being processed may be lost. For this reason as well, the portable device 101 predicts the remaining amount of each secondary battery 102a, 102b and notifies the user of the exhausted state.

  By the way, such remaining amount prediction is performed in consideration of various characteristics of the secondary batteries 102 a and 102 b (lithium ion batteries) built in the battery pack 102. Hereinafter, general characteristics of the lithium ion battery will be described in detail with reference to the drawings.

FIG. 12 is an explanatory diagram showing discharge characteristics with respect to the number of uses of a secondary battery (the figure shows the case of an assembled battery (battery) consisting of three cells).
The capacity of the secondary battery that can be discharged is reduced (that is, the discharge time is shortened) depending on the number of times of use (number of times of charge and discharge; so-called cycle number). For example, in FIG. 12A, the curve A shows the case where the number of cycles is 1, the curves B to D show the cases where the number of cycles is about 250, about 400, and about 500, respectively. This curve shows the case where the number of cycles is about 650 times. That is, as shown in the figure, the discharge time (use time) of the secondary battery decreases as the number of cycles increases. Such a phenomenon is called cycle deterioration characteristics. FIG. 12B is a graph showing the relationship between the discharge capacity of the secondary battery with respect to the number of cycles (the discharge end time is 100%) and the battery voltage, with the time axis in FIG. 12A normalized. It is. As shown in the figure, the battery voltage of the secondary battery becomes almost constant regardless of the number of cycles.

FIG. 13 is an explanatory diagram showing cycle life characteristics of the secondary battery.
This figure is a graph showing the relationship between the number of cycles and the discharge capacity of, for example, three types of secondary batteries. As shown in the figure, the secondary battery has a discharge capacity that increases as the number of cycles increases. Decrease. For example, the curve F in the figure shows that the discharge capacity (capacity at full charge) when the number of cycles of the secondary battery is 600 times decreases to about 30% of the maximum.

FIG. 14 is an explanatory diagram showing deterioration characteristics of the secondary battery depending on the use environment.
This graph is a graph showing the deterioration characteristics when the secondary battery is left for one month in a temperature environment of 45 ° C., for example, the G curve shows before leaving, and the H curve shows after standing. is there. As shown in the figure, the discharge time (use time) of the secondary battery varies depending on the temperature environment in which it is used.

FIG. 15 is an explanatory diagram showing the relationship between the discharge power and the dischargeable capacity with respect to the operating temperature for two types of secondary batteries.
In the figure, curves I to K show the same secondary battery when used at temperatures of 5 ° C., 25 ° C., and 45 ° C., for example. In addition, the curves L to N indicate the case where the same secondary batteries of different types are used at temperatures of, for example, 5 ° C, 25 ° C, and 45 ° C.

  In the figure, for example, the secondary battery (operating temperature 5 ° C.) indicated by the curve I can be used for about 2.8 hours at a discharge power of 10 W, and is the same secondary battery as the secondary battery indicated by the curve K. (Use temperature 45 ° C.) can be used for about 3.2 hours with a discharge power of 10 W. Also, in the secondary battery of a different type, for example, the secondary battery indicated by the curve of L (use temperature 5 ° C.) can be used for about 2.8 hours at a discharge power of 10 W, and is the same secondary battery as that. The secondary battery (operating temperature 45 ° C.) indicated by the curve N can be used for about 3.1 hours at a discharge power of 10 W. As described above, the secondary battery has different dischargeable capacity (use time) depending on the type, use temperature, and discharge power.

  Conventionally, the remaining amount prediction of the secondary battery is performed in consideration of the various characteristics described above. As the remaining amount prediction method, for example, a prediction method based on the battery voltage of the secondary battery, or the secondary battery There is a method of predicting based on the integrated value of the charging current and the discharging current.

FIG. 16 is a schematic diagram illustrating a first conventional configuration example having a remaining amount prediction function.
The portable device 121 is, for example, a notebook personal computer. The portable device 121 includes a battery pack 122 called a smart battery (also called an intelligent battery).

  The battery pack 122 includes a plurality (three in the figure) of secondary batteries 122a to 122c, a protection circuit 123, a discharge control switch 124, a charge control switch 125, a remaining amount meter 126 as a remaining amount predicting means, an EEPROM 127 as a memory, and A first sense resistor 128 is included. FIG. 16 shows only a part of the portable device 121. The portable device 121 is one of the second sense resistor 129, the charger 130, and the microcomputer, for example, a keyboard microcomputer 131. including.

  Each of the secondary batteries 122a to 122c is, for example, a lithium ion battery, and they are connected in series to constitute an assembled battery (battery). The positive terminal of the secondary battery 122a is connected to the positive terminal t1 of the battery pack 122 via the discharge control switch 124, the charge control switch 125, and the first sense resistor 128, and the negative terminal of the secondary battery 122c is The battery pack 122 is connected to the negative terminal t2. Specifically, the discharge control switch 124 and the charge control switch 125 are configured by first and second P-channel MOS transistors, and the source of the discharge control switch 124 is connected to the positive terminal of the secondary battery 122a. The drains of 125 are connected to each other. The source of the charging control switch 125 is connected to the positive terminal t1 of the battery pack 122 via the first sense resistor 128. The transistors of both switches 124 and 125 are connected so that the back gates constitute forward diodes with respect to the charging current and discharging current.

  The protection circuit 123 includes an overcharge prevention circuit and an overdischarge prevention circuit (both not shown). The protection circuit 123 detects the inter-terminal voltage (cell voltage) of each of the secondary batteries 122a to 122c, and when any one of them becomes a specified voltage or lower, that is, when an overdischarge state occurs, the discharge control switch 124 is turned off to inhibit discharge. On the other hand, the protection circuit 123 turns off the charge control switch 125 and inhibits charging when any one of the secondary batteries 122a to 122c exceeds the specified voltage, that is, when overcharged.

  Incidentally, at the time of charging, each of the secondary batteries 122a to 122c is charged by a charging current supplied from the portable device 121 via the charge control switch 125 and the discharge control switch 124 that are turned on. Specifically, in portable device 121, charger 130 is connected to AC adapter 132, which is an external power supply, and controls the charging current based on the value of the current flowing through second sense resistor 129.

Conversely, at the time of discharging, each of the secondary batteries 122 a to 122 c outputs a discharge current to the portable device 121 via the discharge control switch 124 and the charge control switch 125 that are turned on.
The remaining amount meter 126 includes a microcomputer (not shown), measures the charging / discharging current flowing through the first sense resistor 128, and determines the remaining amount based on the integrated current value and each cell voltage detected by the protection circuit 123. Make quantity predictions. The remaining amount meter 126 stores the estimated remaining amount in the EEPROM 127 and outputs it to the keyboard microcomputer 131 provided in the portable device 121, for example. When the remaining amount prediction value is output from the remaining amount meter 126, the keyboard microcomputer 131 displays the remaining battery amount on a display device (not shown).

FIG. 17 is a schematic diagram illustrating a second conventional configuration example having a remaining amount prediction function.
The portable device 141 is, for example, a notebook computer, and the portable device 141 has a battery pack 142 built therein. In the second conventional configuration example, the battery pack 142 includes a current accumulator 143 as a remaining amount predicting unit instead of the remaining amount meter 126 of FIG. Accordingly, the same reference numerals are assigned to other similar components.

  Similarly to the above, the current accumulator 143 measures the charge current / discharge current flowing through the first sense resistor 128 and outputs the current accumulated value to the power supply microcomputer 144 of the portable device 141. Then, the power supply microcomputer 144 calculates a remaining amount prediction value based on the current integrated value output from the current integrator 143, and displays the battery remaining amount on a display device (not shown) based on the calculated value.

By the way, there are the following problems in the prior art.
[1. Problems with remaining capacity prediction]
In the first conventional configuration shown in FIG. 16, the remaining amount meter 126 calculates a remaining amount predicted value based on the cell voltage of each of the secondary batteries 122a to 122c and the integrated value of the charging current and discharging current, Output to the portable device 121. With this configuration, the remaining amount can be predicted with high accuracy, but the remaining amount meter 126 has a microcomputer, and thus there is a problem that the cost of the battery pack 122 increases.

  On the other hand, in the second conventional configuration shown in FIG. 17, since the battery pack 142 does not include a microcomputer, an increase in cost can be suppressed. However, the battery pack 142 includes a current integrator 143 as a remaining amount predicting unit, and the remaining amount prediction of the secondary battery is performed only by detecting the current value. As described above, the discharge capacity of the secondary battery decreases as the number of cycles increases (see FIG. 13). Therefore, there is a problem that the remaining amount prediction cannot be accurately performed only by the remaining amount prediction based on such current integration. In particular, when the battery pack 142 includes a plurality of secondary batteries 122a to 122c, the capacity (inter-terminal voltage) varies, and there is a problem that the accuracy of the remaining amount prediction further decreases. .

[2. Problems with charging]
In the first conventional configuration, the charger 130 detects the charging current flowing through the second sense resistor 129, and performs constant voltage / constant current charging for the secondary batteries 122a to 122c based on the detection result. By the way, in order to perform such constant voltage / constant current charging with high accuracy, it is necessary to improve the accuracy of current detection by the charger 130. Therefore, the second sense resistor 129 provided for current detection is usually a highly accurate one, and there is a problem that the cost of the charger 130 increases. Further, such a high-precision resistor has a large size, and as a result, there is a problem that the charger 130 is enlarged. Such a problem also occurred in the second conventional configuration.

  An object of the battery pack, the semiconductor device, and the portable device incorporating the battery pack is to accurately estimate the remaining amount of the secondary battery and charge the secondary battery while reducing the cost.

  In this battery pack, the measuring means provided in the battery pack samples the current flowing into or out of the secondary battery, samples the voltage of the secondary battery, and based on the result of the sampling. Then, the current flowing into or out of the secondary battery and the voltage of the secondary battery are measured, and the measurement results are output to the portable device. Then, the data processing means provided in the portable device performs the remaining amount prediction based on the current and voltage measurement results output from the measurement means. Thereby, it is possible to accurately predict the remaining amount while reducing the cost of the battery pack.

The analog-digital conversion circuit of the battery pack simultaneously converts the analog signals sampled simultaneously into digital signals, and sequentially outputs the digital signals.
The analog-digital conversion circuit of the battery pack sequentially converts the analog signals sampled at the same time into digital signals and outputs them.

The battery pack outputs the digital signal to the outside.
The semiconductor device includes a current detection circuit that detects current flowing into or out of the secondary battery, a voltage detection circuit that detects individual voltages of the secondary battery, the current detection circuit, and the voltage And an analog-digital conversion circuit for simultaneously converting each analog signal output from the detection circuit into a digital signal. The analog-digital conversion circuit simultaneously samples a reference voltage generated internally or supplied from the outside and at least one analog signal, and outputs a digital signal obtained by converting the reference voltage and the analog signal, respectively.

The semiconductor device includes a switch provided between the secondary battery and a terminal of the battery pack, and a protection circuit that controls charging / discharging of the secondary battery.
The portable device is configured to incorporate or attach the above battery pack.

  As described above, according to the battery pack, the semiconductor device, and the portable device incorporating the battery pack, the remaining capacity of the secondary battery is predicted and the secondary battery is accurately charged while reducing the cost. be able to.

(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS.
FIG. 1 is a block circuit diagram showing a schematic configuration of a portable electronic device (hereinafter referred to as a portable device) incorporating the battery pack of the present embodiment.

The portable device 11 is connected to the battery pack 12. The portable device 11 can be connected to an AC adapter 13 as an external power source.
The battery pack 12 includes a battery 14, a discharge control switch 15, a charge control switch 16, a protection circuit 17, a first sense resistor 18, a temperature sensor 19 as a temperature detection circuit, and a measurement circuit 20 (measurement means). The portable device 11 includes a power supply microcomputer 21 as a data processing means, a charger 22, an output switch 23, a coil 24, and a second sense resistor 25. The portable device 11 shown in FIG. 1 shows a part of the power supply device.

  The battery 14 built in the battery pack 12 includes one or a plurality of (for example, three in the figure) secondary batteries 14a to 14c. In the present embodiment, each of the secondary batteries 14a to 14c is, for example, a lithium ion battery. It is configured. The positive side terminal of the secondary battery 14a is connected to the positive side terminal t1 of the battery pack 12 as the first terminal via the discharge control switch 15, the charge control switch 16 and the first sense resistor 18, and its terminal. t1 is connected to the plus terminal t11 of the portable device 11. On the other hand, the minus terminal of the secondary battery 14 c is connected to the minus terminal t 2 of the battery pack 12, and the terminal t 2 is connected to the minus terminal t 22 of the portable device 11.

  The discharge control switch 15 and the charge control switch 16 are composed of P-channel MOS transistors, the drains of both the switches 15 and 16 are connected to each other, and the gates are connected to the protection circuit 17, respectively. The source of the discharge control switch 15 is connected to the positive terminal of the secondary battery 14 a, and the source of the charge control switch 16 is connected to the first sense resistor 18. The transistors of both the switches 15 and 16 are connected so that the back gates constitute forward diodes with respect to the charging current and discharging current.

  The protection circuit 17 has a function as a voltage detection circuit that detects voltages (cell voltages) between the terminals of the secondary batteries 14 a to 14 c, and outputs a voltage detection signal A 1 corresponding to the detected voltage value to the measurement circuit 20. The protection circuit 17 controls on / off of the discharge control switch 15 and the charge control switch 16 according to the detected cell voltages. Specifically, when the discharge control switch 15 is turned on by the protection circuit 17, the secondary batteries 14 a to 14 c can be discharged to the portable device 11. Conversely, when the charging control switch 16 is turned on by the protection circuit 17, the portable device 11 can charge the secondary batteries 14a to 14c.

  The protection circuit 17 includes an overdischarge prevention circuit that prevents overdischarge of the secondary batteries 14a to 14c and an overcharge prevention circuit that prevents overcharge (both not shown). More specifically, the overdischarge prevention circuit turns off the discharge control switch 15 and inhibits discharge when any one of the secondary batteries 14a to 14c has a specified voltage or lower. The overcharge prevention circuit turns off the charge control switch 16 to inhibit charging when any one of the secondary batteries 14a to 14c has a specified voltage or higher. Thereby, the protection circuit 17 prevents deterioration of the functions of the secondary batteries 14a to 14c.

  The temperature sensor 19 detects the temperature of the battery 14 and outputs the temperature detection signal A2 to the measurement circuit 20. A temperature sensor may be provided so as to detect the temperature of each of the secondary batteries 14 a to 14 c built in the battery 14.

  The measurement circuit 20 includes a current detection amplifier circuit (hereinafter referred to as current detection circuit) 26, an analog-digital conversion circuit (hereinafter referred to as AD conversion circuit) 27, a rewritable nonvolatile memory 28, and an interface circuit (hereinafter referred to as I / F). Circuit) 29.

  The inverting input terminal of the current detection circuit 26 is connected to the high potential side terminal of the first sense resistor 18, and the non-inverting input terminal is connected to the low potential side terminal of the resistor 18. The current detection circuit 26 detects a discharge current from the battery 14 flowing through the first sense resistor 18 or a charging current from the portable device 11 and outputs a current detection signal A3 corresponding to the current value to the AD conversion circuit 27. To do. Specifically, the current detection circuit 26 inputs a potential across the first sense resistor 18 and outputs a current detection signal A3 corresponding to the potential difference. Therefore, the current detection circuit 26 increases the level of the current detection signal A3 when the discharge current or the charging current flowing through the first sense resistor 18 increases, and decreases the level of the current detection signal A3 when it decreases.

  A voltage detection signal A 1 from the protection circuit 17, a temperature detection signal A 2 from the temperature sensor 19, and a current detection signal A 3 from the current detection circuit 26 are input to the AD conversion circuit 27. The AD conversion circuit 27 converts the detection signals A1 to A3 input as analog signals into digital signals, and outputs the digital values to the power supply microcomputer 21 provided in the portable device 11 via the I / F circuit 29. To do.

  The power supply microcomputer 21 receives the digital value output from the measurement circuit 20 as a measurement value for predicting the remaining amount, and displays the remaining battery level on a display device (not shown) according to the predicted remaining amount calculated based on the measured value. . Each time the power supply microcomputer 21 performs the remaining amount prediction, the remaining amount predicted value calculated thereby and the usage state data of the secondary batteries 14a to 14c at that time (for example, the discharge current amount, the total usage time, the number of cycles, etc.) ) Is stored in the memory 28 in the measurement circuit 20. In the present embodiment, the power supply microcomputer 21 performs the remaining amount prediction, but the data processing means is not limited to the power supply microcomputer 21 and may be performed by another microcomputer included in the portable device 11. .

The charger 22 includes a current detection amplifier circuit (hereinafter referred to as current detection circuit) 31, an error amplifier circuit 32, a voltage detection amplifier circuit (hereinafter referred to as voltage detection circuit) 33, and a PWM comparison circuit 34.
The inverting input terminal of the current detection circuit 31 is connected to the low potential side terminal of the second sense resistor 25, and the non-inverting input terminal is connected to the high potential side terminal of the resistor 25. The current detection circuit 31 detects a current value of the charging current Ic supplied from the AC adapter 13 to the battery 14 during charging, and outputs a current detection signal A4 corresponding to the current value to the error amplification circuit 32. Specifically, the current detection circuit 31 inputs a potential across the second sense resistor 25 and outputs a current detection signal A3 corresponding to the potential difference. Therefore, the current detection circuit 31 increases the level of the current detection signal A4 when the charging current Ic increases, and conversely decreases the level of the current detection signal A4 when the charging current Ic decreases.

  The current detection signal A4 from the current detection circuit 31 is input to the inverting input terminal of the error amplifier circuit 32, and the first reference voltage Vref1 is input to the non-inverting input terminal. The voltage value of the first reference voltage Vref1 is variably controlled by the power supply microcomputer 21. More specifically, the power supply microcomputer 21 determines the voltage value of the first reference voltage Vref1 according to the current measurement value in the measurement circuit 20. Then, the error amplification circuit 32 compares the first reference voltage Vref1 with the current detection signal A4, and outputs an error signal A5 obtained by amplifying the difference voltage between the two voltages to the PWM comparison circuit 34.

  The inverting input terminal of the voltage detection circuit 33 is connected to the low potential side terminal of the second sense resistor 25, and the charging voltage Vc supplied from the AC adapter 13 to the battery 14 is input to the inverting input terminal. The non-inverting input terminal of the voltage detection circuit 33 is supplied with the second reference voltage Vref2. The voltage detection circuit 33 compares the charging voltage Vc with the second reference voltage Vref2, and outputs a voltage detection signal A6 obtained by amplifying the difference voltage between the two voltages to the PWM comparison circuit 34.

  The PWM comparison circuit 34 receives a triangular wave signal from a triangular wave oscillation circuit (not shown), and compares the level of the triangular wave signal with the signal having the smaller level of the error signal A5 and the voltage detection signal A6. For example, in the comparison, the PWM comparison circuit 34 outputs a pulse signal S1 that is at the L level during the period in which the level of the triangular wave signal is larger and is at the H level during the period in which the triangular wave signal is smaller.

  The output switch 23 is composed of an N-channel MOS transistor, and the pulse signal S1 from the PWM comparison circuit 34 is input to the gate thereof. The source of the output switch 23 is connected to the coil 24, and the drain is connected to the AC adapter 13. This output switch 23 is ON / OFF controlled based on the pulse signal S1 output from the PWM comparison circuit 34. Based on the switching operation, the charging current Ic and the charging voltage Vc from the AC adapter 13 are constant at predetermined values. Control to be.

FIG. 2 is a schematic block diagram showing the AD conversion circuit 27 of FIG.
The AD conversion circuit 27 has an analog input AVref as an analog power supply generated internally or supplied from the outside, a reference voltage Am, and a plurality of analog inputs (only one is shown in FIG. 2 for simplification). A signal An is input. The reference voltage Am is supplied from the outside as shown by a two-dot chain line in the same figure as the analog voltage AVref, or is given as an internal reference voltage as shown by a broken line.

  In this embodiment, the analog input signal An is the voltage detection signal A1 from the protection circuit 17, the temperature detection signal A2 from the temperature sensor 19, or the current detection signal A3 from the current detection circuit 26. The AD conversion circuit 27 outputs digital values Dm and Dn generated by analog-to-digital conversion of the reference voltage Am and the analog input signal An with an analog voltage AVref and, for example, analog ground as an input voltage range.

Hereinafter, the AD conversion system of this embodiment will be described with reference to FIGS.
FIG. 4 is a block circuit diagram showing a specific configuration of the AD conversion circuit 27. In the figure, the analog voltage AVref and the reference voltage Am are not shown, and the voltage detection signal A1, the temperature detection signal A2, and the current detection signal A3 are shown as the analog input signal An.

  As shown in FIG. 4A, the AD conversion circuit 27 is a sampling hold circuit for sampling the analog values of the voltage detection signal A1, the temperature detection signal A2, and the current detection signal A3 input as the analog input signal An. (Hereinafter referred to as S / H circuit) 41a to 41c, a select circuit 42 and an AD converter 43 are included.

  Each of the S / H circuits 41a to 41c is constituted by, for example, a flip-flop, and outputs analog values (hereinafter referred to as sampling values) of detection signals A1 to A3 simultaneously sampled and held based on a clock signal (not shown) to the select circuit 42. To do. The select circuit 42 sequentially outputs the sampling values to the AD converter 43, and the AD converter 43 outputs digital values D1 to D3 generated by sequentially analog-digital conversion of the input sampling values.

  In such an AD conversion method, a plurality of analog input signals An (that is, the respective detection signals A1 to A3) given as measurement target values are simultaneously sampled by a plurality of S / H circuits 41a to 41c provided corresponding thereto. Therefore, the sampling accuracy is improved. As a result, the measurement circuit 20 shown in FIG. 1 can accurately measure voltage, current, and temperature.

Note that the following AD conversion method may be used by changing the configuration of the AD conversion circuit 27 shown in FIG. 4A as shown in FIG.
This AD conversion circuit 27 includes S / H circuits 41a to 41c for simultaneously sampling the detection signals A1 to A3 as in FIG. 4A, and AD converters 44a to 44c provided corresponding to them. Includes a select circuit 45. That is, in the AD conversion circuit 27 configured as described above, the sampling values of the detection signals A1 to A3 sampled at the same time are input to the AD converters 44a to 44c, respectively. Are simultaneously converted from analog to digital and output to the select circuit 45. The select circuit 45 sequentially outputs digital values D1 to D3 output from the AD converters 44a to 44c. Even when the AD conversion circuit 27 is configured in this manner, the sampling accuracy is improved as in the configuration of FIG. As a result, the measurement circuit 20 can accurately measure voltage, current, and temperature.

FIG. 3 is a flowchart for explaining the AD conversion method of this embodiment.
The AD conversion circuit 27 outputs a digital value Dm obtained by analog-to-digital conversion of the reference voltage Am using the supplied analog voltage AVref and analog ground as an input voltage range (step 51).

  Next, similarly, the AD conversion circuit 27 uses the analog voltage AVref and the analog ground as the input voltage range, and an analog input signal An (in this embodiment, a voltage detection signal A1, a temperature detection signal A2, a current detection signal) input as a measurement target. The digital value Dn of A3) is output (step 52). The power supply microcomputer 21 calculates a measured input value of the analog input signal An based on the two digital values Dm and Dn and the value of the reference voltage Am stored in advance (step 53).

  In such an AD conversion method, the analog input signal An (voltage value, current value, temperature) does not depend on the voltage value of the analog voltage AVref supplied to the AD conversion circuit 27, and the reference voltage Am is supplied to the AD conversion circuit 27. Is calculated based on the voltage value given as.

More specifically, for example, when the AD conversion circuit 27 is configured to output a 10-bit digital signal, the value of the reference voltage Am is the digital value Dm and the input voltage range (in this case, the value of the analog voltage AVref). And
Am = (Dm / 1024) × AVref (1)
Is required. Similarly, the value of the analog input signal An is derived from the digital value Dn and the input voltage range.
An = (Dn / 1024) × AVref (2)
Is required. Therefore, the value of the analog input signal An is obtained from the above equations (1) and (2).
An = (Dn / Dm) × Am (3)
Is required. Therefore, if the value of the reference voltage Am is known, the value of the analog voltage AVref is obtained by obtaining a digital value Dm obtained by A / D converting the reference voltage Am and a digital value Dn obtained by A / D converting the analog input signal An. The value of the analog input signal An can be obtained without depending on the above.

  Generally, when the value of the analog input signal An is to be obtained, the value of the analog voltage AVref is known at the time of designing the LSI, and therefore only the above equation (2) may be used. However, in that case, it is necessary to match the analog voltage AVref with high accuracy. For example, when the analog voltage AVref is designed at 3V, the analog voltage AVref supplied to the actual A / D conversion circuit must be exactly 3V. As described above, the power supply circuit that generates the analog voltage AVref with high accuracy requires many circuit elements, so that the cost of the LSI increases.

  On the other hand, the value of the analog voltage AVref is not required in the above equation (3). What is desired for the analog voltage AVref is that it is stable during A / D conversion of the reference voltage Am and the analog input signal An. Such a stabilized power supply circuit has a smaller number of circuit elements and is less expensive than a highly accurate power supply circuit.

  Therefore, in the present embodiment, the AD conversion circuit 27 does not require the accuracy of a high-precision analog power source for performing analog-digital conversion, that is, the analog voltage AVref. As a result, the AD conversion circuit 27 can be configured easily and at low cost.

Next, the operation of the portable device 11 incorporating such a battery pack 12 will be described.
First, the remaining amount prediction method will be described in detail.
In the battery pack 12, the measurement circuit 20 detects the current value of the charging current flowing into the battery 14 (secondary batteries 14 a to 14 c) contained in the battery pack 12 or the discharging current flowing out from the battery 14, and The analog-digital converted value is output to the power supply microcomputer 21 as a current measurement value. Further, the measurement circuit 20 outputs, to the power supply microcomputer 21, values obtained by analog-digital conversion of the voltage value detected by the protection circuit 17 and the temperature detected by the temperature sensor 19 as voltage measurement values and temperature measurement values, respectively.

  The power supply microcomputer 21 calculates a remaining amount prediction value based on each measurement value output from the measurement circuit 20 and outputs it to a display device (not shown). Further, the power supply microcomputer 21 stores the remaining amount predicted value calculated at this time and the usage state data of the secondary batteries 14 a to 14 c at that time in the memory 28 in the measurement circuit 20. Thereby, in the remaining amount prediction after that, the power supply microcomputer 21 determines the remaining amount based on the remaining amount predicted value and the usage state data stored in the memory 28 in addition to each measured value output from the measuring circuit 20. Make a prediction.

  In such a remaining amount prediction method, a microcomputer or the like for performing the remaining amount prediction is not required in the battery pack 12, and the remaining amount prediction is performed by the power supply microcomputer 21 provided in the portable device 11. Thereby, the remaining amount can be predicted with high accuracy while reducing the cost.

Next, the charge control method will be described in detail.
When the AC adapter 13 is connected to the portable device 11 and charging of the battery 14 is started, the charger 22 monitors the charging current Ic and the charging voltage Vc supplied from the AC adapter 13 and those current values are monitored. And charging is performed by controlling the output switch 23 so that the voltage value becomes constant. That is, the charger 22 performs constant voltage / constant current charging for the battery 14.

  When the battery 14 is charged, the measurement circuit 20 of the battery pack 12 detects the charging current flowing through the first sense resistor 18. The power supply microcomputer 21 sets the voltage value of the first reference voltage Vref1 input to the current detection circuit 31 based on the current measurement value from the measurement circuit 20. Accordingly, the charger 22 performs charging by correcting the charging current value and the charging voltage value based on the measured value of the charging current by the measuring circuit 20. In such a charge control system, it is possible to perform constant voltage / constant current charging with high accuracy by feeding back the current measurement result in the battery pack 12, and shorten the charging time.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The battery pack 12 includes a measurement circuit 20 that measures each current value of charging current / discharge current, each voltage value of the secondary batteries 14 a to 14 c, and the temperature of the battery 14. The measurement circuit 20 outputs the current measurement value, the voltage measurement value, and the temperature measurement value to the power supply microcomputer 21 provided in the portable device 11, and the power supply microcomputer 21 predicts the remaining amount of the battery 14 based on them. Therefore, it is possible to accurately predict the remaining amount while reducing the cost of the battery pack 12.

  (2) The measurement circuit 20 includes a memory 28, and the power supply microcomputer 21 stores, in the memory 28, the remaining amount predicted value calculated thereby and the usage status data of the secondary batteries 14 a to 14 c at that time. Store. Therefore, since the power supply microcomputer 21 uses the data stored in the memory 28 to perform the remaining amount prediction thereafter, the remaining amount prediction can be performed more accurately.

  (3) The AD conversion circuit 27 outputs the digital value Dn of the reference voltage Am set to it and the digital value Dn of the analog input signal An, and the power supply microcomputer 21 outputs the digital values Dm and Dn and the reference voltage Am. Based on the value, the measurement input value (current value, voltage value, temperature) of the analog input signal An is calculated. As a result, a highly accurate analog power supply (analog voltage AVref) can be eliminated from the AD conversion circuit 27, and the AD conversion circuit 27 can be easily configured at low cost. Such an AD conversion circuit 27 can detect the current value, the voltage value, and the temperature with high accuracy while eliminating the need for the high-precision analog voltage AVref.

  (4) When charging the battery 14, the charger 22 is charged with a current value reflecting a current measurement result in the measurement circuit 20 in the battery pack 12. Thereby, the constant voltage / constant current charging with respect to the battery 14 can be performed with high accuracy, and the charging time can be shortened.

In addition, you may implement the said embodiment in the following aspects.
-In 1st embodiment, you may change the structure of FIG. 1 as shown in FIG. That is, in the charger 22 a of the portable device 11, the control voltage signal from the power supply microcomputer 21 is input to the inverting input terminal of the error amplifier circuit 32. In this way, the control voltage signal generated by the power supply microcomputer 21 based on the current measurement result from the measurement circuit 20 is directly input to the error amplification circuit 32 so that the measurement result in the battery pack 12 is fed back during constant current control. By doing so, the current sense resistor (second sense resistor 25 in FIG. 1) of the charger 22a may be reduced.

(Second embodiment)
Hereinafter, a second embodiment will be described with reference to FIGS.
FIG. 6 is a block circuit diagram showing a schematic configuration of a portable device 62 incorporating the battery pack 61 of the present embodiment. In addition, this embodiment adds the voltage control terminal t3 newly to the battery pack 12 of 1st embodiment, and changes a part of charge control system mentioned above. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals, and a detailed description thereof is partially omitted.

  The battery pack 61 includes a voltage control terminal t3 as a second terminal, and the voltage control terminal t3 is connected to an input terminal t33 provided in the portable device 62. The input terminal t33 is connected to the current detection circuit 64 and the inverting input terminal of the voltage detection circuit 65 in the charger 63.

  The non-inverting input terminal of the current detection circuit 64 is connected to the low potential side terminal of the coil 24. Here, the portable device 62 of the present embodiment has a configuration in which the second sense resistor 25 (see FIG. 1) in the portable device 11 of the first embodiment is omitted. That is, a signal having substantially the same potential as that of the positive terminal t1 (first terminal) of the battery pack 61 is input to the non-inverting input terminal of the current detection circuit 64. The second reference voltage Vref2 is input to the non-inverting input terminal of the voltage detection circuit 65 as in the first embodiment.

  The protection circuit 66 of the battery pack 61 detects the battery voltage Vb of the battery 14 (that is, the battery voltage on the plus side of the secondary battery 14a) and outputs the battery voltage Vb to the voltage control terminal t3. Accordingly, the battery voltage Vb is input to the inverting input terminals of the current detection circuit 64 and the voltage detection circuit 65 of the charger 63.

  Thereby, in the charger 63 of the present embodiment, the current detection circuit 64 substantially detects the charging current flowing through the battery pack 61, and sets the current detection signal A4 having a potential corresponding to the current value in the same manner as described above. Output to the error amplifier circuit 32. The voltage detection circuit 65 detects the battery voltage Vb in the battery pack 61, compares the battery voltage Vb with the second reference voltage Vref2, and generates a voltage detection signal A6 obtained by amplifying the difference voltage between the two voltages. In the same manner as described above, the signal is output to the PWM comparison circuit 34.

Next, a charge control method in the portable device 62 incorporating the battery pack 61 of the present embodiment will be described with reference to some drawings.
When the AC adapter 13 is connected to the portable device 62 and charging of the battery 14 is started, the charger 63 monitors the charging current and the battery voltage Vb flowing in the battery pack 61, and those current values and voltages are monitored. The output switch 23 is controlled so that the value is constant, and constant voltage / constant current charging is performed.

  When the battery 14 is charged, the measurement circuit 20 of the battery pack 61 detects the charging current flowing through the first sense resistor 18. The power supply microcomputer 21 sets the voltage value of the first reference voltage Vref1 input to the current detection circuit 64 based on the current measurement value from the measurement circuit 20. Thereby, the charger 63 performs charging with the charging current value and the charging voltage value reflecting the measured value of the charging current by the measuring circuit 20. In such a charging control method, the charger 63 performs constant voltage / constant current control during charging based on the charging current in the battery pack 61 and the battery voltage Vb, and additionally, the current measurement result in the battery pack 61 is displayed. By performing the feedback, it is possible to perform constant voltage / constant current charging with higher accuracy than in the first embodiment. Therefore, the charging time can be further shortened.

  FIG. 7 is an explanatory diagram showing the charging characteristics of the present embodiment. In the figure, the set voltage at the time of constant voltage charging of the battery 14 shown in FIG. 6 is, for example, 12.6 V (volt) (that is, the rated voltage of the cell voltage of each of the secondary batteries 14 a to 14 c is 4.2 V, respectively). Set to).

  As shown in FIG. 7A, at the start of charging by the charging control method of the present embodiment, the charging voltage for the battery 14 becomes a voltage that reaches approximately 12.6 V, and then the battery 14 is charged at a constant voltage / constant current. Is charged toward 12.6V. This charging is terminated when the charging current for the battery 14 reaches a current value of approximately 1/20 or less of the battery capacity of the battery 14. Thus, the charger 63 charges the battery 14 with a voltage of about 12.6 V (which does not exceed the voltage value of 12.6 V), which is a set voltage value for constant voltage charging, at the start of charging, so the charging time is shortened. Is done. FIG. 7B is an explanatory diagram showing charging characteristics when the voltage control terminal t3 as the second terminal is not provided. As can be seen from a comparison between FIGS. 7A and 7B, when the voltage control terminal t3 is provided (FIG. 7A), the charging time of the battery 14 is shortened.

  Further, in the present embodiment, the charger 63 detects the battery voltage Vb of the battery 14, so that the charging voltage for the battery 14 is highly accurate in consideration of the voltage drop in the battery pack 61 and the impedance of the protection circuit 66. Set. Thereby, the charge amount with respect to the battery 14 can be controlled accurately.

  Hereinafter, the relationship between the charging voltage and the discharge capacity stored in the secondary battery will be described with reference to FIG. FIG. 8 shows a case where the rated voltage of the secondary battery is set to, for example, 4.2V.

  As shown in FIG. 8A, when this secondary battery is charged at a rated voltage of 4.2 V, its discharge capacity becomes, for example, about 1900 mAH. Now, when the secondary battery is charged at 4.3 V exceeding the rated voltage 4.2 V, the discharge capacity increases to about 2060 mAH. Conversely, when the secondary battery is charged at 4.1 V, which is a rated voltage of 4.2 V or less, the discharge capacity is reduced to about 1640 mAH. FIG. 8B shows the discharge capacity ratio with respect to each charge voltage, where 1 is the discharge capacity stored when charging at the rated voltage of 4.2V.

  The higher the charging voltage is, the larger the capacity stored in the secondary battery is. However, when charging is performed at a voltage value exceeding the rated voltage of 4.2 V, the secondary battery is deteriorated and the cycle life is shortened. On the other hand, when the charging voltage is lower than the rated voltage of 4.2 V, the capacity stored in the secondary battery becomes small. Therefore, it is desirable that the charging voltage for the secondary battery does not exceed the rated voltage 4.2V and is a voltage value closer to the voltage value 4.2V.

  In the present embodiment, the charger 63 detects the battery voltage Vb. Therefore, the charging voltage with respect to the battery 14 is controlled with high accuracy, so that the charging capacity stored in the battery 14 can be increased as much as possible within a specified range.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The battery pack 61 is provided with a voltage control terminal t3 as a second terminal. Thereby, in the charger 63, the current detection circuit 64 substantially detects the charging current flowing in the battery pack 61, and the voltage detection circuit 65 considers the voltage drop in the battery pack 61 and the impedance of the protection circuit 66. The battery voltage Vb of the battery 14 is detected. As in the first embodiment, the current measurement result by the measurement circuit 20 in the battery pack 61 is reflected in the constant current control. Thereby, since the charging voltage with respect to the battery 14 can be controlled with high accuracy, the amount of charge can be accurately controlled, and the charging time can be further shortened.

  (2) Since the voltage control terminal t3 is provided and the charger 63 monitors the charging current and the charging voltage in the battery pack 61, the second sense resistor 25 in the portable device 11 can be dispensed with. . Accordingly, it is possible to contribute to cost reduction of the portable device 11 and circuit miniaturization.

(Third embodiment)
Hereinafter, a third embodiment will be described with reference to FIG.
FIG. 9 is a block circuit diagram showing a schematic configuration of a portable device 72 incorporating the battery pack 71 of the present embodiment. In the present embodiment, the configuration of the second embodiment is partially changed, and the power control method of the portable device 72 incorporating the battery pack 71 will be described. Therefore, the same components as those in the second embodiment are denoted by the same reference numerals, and a detailed description thereof is partially omitted.

  The battery pack 71 includes a voltage control terminal t3 as a second terminal as in the second embodiment. The voltage control terminal t3 is connected to the current detection circuit 64 in the charger 63 and the inverting input terminal of the voltage detection circuit 65 via the input terminal t33 of the portable device 72 (not shown in FIG. 9). 6). Similarly, the plus side terminal t1 (first terminal) of the battery pack 71 is connected to the non-inverting input terminal of the current detection circuit 64 via the plus side terminal t11 of the portable device 72 (in FIG. 9). This is omitted; see FIG.

  In the portable device 72, the power supply microcomputer 21 is connected to a standby power supply 73 for supplying power when the portable device 72 is in a standby state. The standby power supply 73 connects the diode 74 and the input terminal t <b> 33 of the portable device 72. And is connected to the voltage control terminal t3 of the battery pack 71.

  The protection circuit 75 detects the cell voltages of the secondary batteries 14a to 14c, and the measurement circuit 20 outputs the voltage measurement values of the secondary batteries 14a to 14c to the power supply microcomputer 21 based on the detection results. The power supply microcomputer 21 outputs a switch control signal SWC to the protection circuit 75 based on each voltage measurement value, and the protection circuit 75 turns on / off the discharge control switch 15 and the charge control switch 16 based on the switch control signal SWC. To control.

  The protection circuit 75 includes a standby power control switch 76 for controlling the positive terminal of the battery 14 and the voltage control terminal t3 to be connected / disconnected, and based on the switch control signal SWC from the power supply microcomputer 21. The standby power control switch 76 is turned on / off. More specifically, the protection circuit 75 turns on the standby power control switch 76 in response to a switch control signal SWC for turning off the discharge control switch 15. Conversely, the protection circuit 75 turns off the standby power control switch 76 in response to a switch control signal SWC for turning on the discharge control switch 15.

  Therefore, in the present embodiment, the protection circuit 75 functions as a standby control unit when the portable device 72 is on standby. The protection circuit 75 turns off both the discharge control switch 15 and the standby power control switch 76 when detecting the overdischarge state of the secondary batteries 14a to 14c.

  In the portable device 72 incorporating such a battery pack 71, in the standby state of the portable device 72, the discharge control switch 15 is turned off and the standby power control switch 76 is turned on. Therefore, in the standby state, unnecessary power consumption in the portable device 72 is prevented (power supply from the battery 14 to the DC-DC converter 77 is cut off). At this time, the standby power source 73 is turned off from the battery 14. Only operating power necessary and sufficient for driving is supplied.

  In the present embodiment, when the battery 14 is overdischarged, the standby power control switch 76 is also turned off together with the discharge control switch 15. Therefore, overdischarge of the battery 14 is also reliably prevented.

FIG. 10 is a schematic block diagram showing a conventional configuration example for the circuit configuration of FIG. In the figure, the charger included in the portable device 81 is omitted.
The portable device 81 includes a battery pack 82, and the battery pack 82 includes a battery 83, a first discharge control switch 84, a charge control switch 85, a protection circuit 86, a sense resistor 87, and an ammeter 88. The portable device 81 includes a second discharge control switch 89, a power supply microcomputer 90, a standby power supply 91, DC-DC converters 92a and 92b, and the like.

  In the portable device 81, the power supply microcomputer 90 is connected to the second discharge control switch 89, and this discharge control switch 89 is connected to the DC-DC converters 92a and 92b. The power supply microcomputer 90 is connected to the output terminal of the standby power supply 91, and the input terminal of the standby power supply 91 is connected to the plus terminal t 1 of the battery pack 82 via the diode 93.

  The power supply microcomputer 90 outputs a switch control signal SWC to the protection circuit 86 based on the current detection result from the ammeter, and the protection circuit 86 turns on / off the first discharge control switch 84 and the charge control switch 85 based on the switch control signal SWC. Control off. The power supply microcomputer 90 controls on / off of the second discharge control switch 89 based on a control signal from the standby power supply 91.

  In such a configuration, in the standby state of the portable device 81, operating power is supplied from the battery 83 to the standby power supply 91 via the first discharge control switch 84 and the charge control switch 85. Therefore, in the standby state, power is supplied from the battery 83 to a circuit that does not require the operation of the portable device 81, so that power is consumed unnecessarily.

As described above, according to the present embodiment, the following effects can be obtained.
(1) The protection circuit 75 includes a standby power control switch 76 that is turned on during standby based on a switch control signal SWC from the power microcomputer 21. In such a configuration, a special control circuit or the like for driving and controlling the standby power source 73 is not required, and while the cost is reduced by suppressing the increase in the number of parts, the portable device 72 is useless in the standby state. It is possible to reliably prevent power consumption.

In addition, you may implement each said embodiment in the following aspects.
-Although the battery 14 was comprised from the secondary battery 14a-14c of 3 cells, the number of cells of the secondary battery incorporated in the battery 14 is not limited only to it.

-Although each secondary battery 14a-14c was connected in series, it is good also as a connection structure including parallel connection or series connection and parallel connection.
The characteristics of the above embodiments are summarized as follows.
(Supplementary note 1) A method for predicting the remaining amount of a secondary battery provided in one or more battery packs built in a portable device,
The measurement means in the battery pack measures the current flowing into or out of the secondary battery and the voltage of the secondary battery, and the data processing means in the portable device is from the measurement means. A remaining amount prediction method, wherein the remaining amount is predicted based on a measurement result of the output current and voltage.
(Additional remark 2) The said measurement means measures the temperature of the said secondary battery,
The remaining amount prediction method according to claim 1, wherein the data processing unit performs remaining amount prediction based on the measurement result of the temperature together with the measurement result of the current and the voltage output from the measurement unit. .
(Supplementary Note 3) The measuring means includes a memory,
The supplementary note 1 or 2, wherein the data processing means stores the calculated remaining amount prediction value and the usage state data of the secondary battery in the memory every time the remaining amount prediction is performed. Remaining amount prediction method.
(Additional remark 4) The said measurement means is provided with the analog-digital conversion circuit which converts the analog input signal made into a measurement object into a digital signal, and outputs it,
The data processing means includes a first digital signal obtained by converting a reference voltage internally generated or supplied from the outside by the analog-digital conversion circuit, a second digital signal obtained by converting the analog input signal, and the reference 4. The remaining capacity predicting method according to any one of appendices 1 to 3, wherein the voltage value of the analog input signal is calculated from a voltage value.
(Additional remark 5) The said analog-digital conversion circuit samples the several analog input signal made into a measurement object simultaneously, The remaining amount prediction method of Additional remark 4 characterized by the above-mentioned.
(Additional remark 6) The said analog-digital conversion circuit converts the said several analog input signal sampled simultaneously into a digital signal simultaneously, and outputs each digital signal sequentially, The remaining amount prediction method of Additional remark 5 characterized by the above-mentioned.
(Supplementary note 7) The remaining amount prediction method according to supplementary note 5, wherein the analog-digital conversion circuit sequentially converts the plurality of analog input signals sampled and held simultaneously into digital signals and outputs the digital signals.
(Appendix 8) An analog-digital conversion circuit for converting an input analog input signal into a digital signal,
An analog-to-digital conversion circuit that outputs a digital signal obtained by converting an internally generated reference voltage and at least one analog input signal.
(Supplementary note 9) The analog-digital conversion circuit according to supplementary note 8, wherein the reference voltage and at least one analog input signal are simultaneously sampled.
(Supplementary note 10) The analog-digital conversion circuit according to supplementary note 9, wherein the plurality of analog input signals sampled at the same time are simultaneously converted into digital signals, and each digital signal is sequentially output.
(Supplementary note 11) The analog-digital conversion method according to supplementary note 9, wherein the plurality of analog input signals sampled and held at the same time are sequentially converted into digital signals and output.
(Additional remark 12) It is the charge control method which charges with respect to the secondary battery in the battery pack connected with the said portable apparatus with the charger incorporated in a portable apparatus,
The charger is charged based on a measurement result obtained by measuring a charging current and a charging voltage supplied from an external power source, and a measurement result from a measuring unit in the battery pack that measures a current flowing into the secondary battery. Charge control method characterized by performing constant voltage / constant current control.
(Additional remark 13) It is the charge control method which charges with respect to the secondary battery in the battery pack connected with the said portable apparatus with the charger incorporated in a portable apparatus,
The battery pack includes a first terminal for supplying a charging current and a charging voltage from an external power source to the secondary battery, and a second terminal for outputting a signal having substantially the same potential as the battery voltage of the secondary battery. With a terminal,
The charger is a constant voltage during charging based on a measurement result of measuring a charging current flowing into the first terminal and a measurement result of measuring a potential difference between the first terminal and the second terminal. A charge control method characterized by performing constant current control.
(Supplementary Note 14) A charging control method for charging a secondary battery in a battery pack connected to the portable device by a charger built in the portable device,
The battery pack includes a first terminal for supplying a charging current and a charging voltage from an external power source to the secondary battery, and a second terminal for outputting a signal having substantially the same potential as the battery voltage of the secondary battery. With a terminal,
The charger flows into the secondary battery, a measurement result obtained by measuring a charging current flowing into the first terminal, a measurement result obtained by measuring a potential difference between the first terminal and the second terminal. A charge control method characterized by performing constant voltage / constant current control during charging based on a measurement result from a measuring means in the battery pack for measuring current.
(Supplementary Note 15) A power supply control method for a portable device including a battery pack including one or more secondary batteries,
The battery pack has a first terminal for supplying power from the secondary battery to the portable device, and a second terminal for outputting a signal having substantially the same potential as the battery voltage of the secondary battery. With terminals,
The standby control means of the battery pack shuts off power supply from the first terminal to the portable device and activates a standby power source of the portable device at the second terminal during the standby. The power supply control method characterized by outputting from.
(Supplementary Note 16) When the secondary battery is in an overdischarged state, the standby control means cuts off the power supply from the first terminal and invalidates the signal output from the second terminal. The power supply control method according to supplementary note 15, wherein
(Supplementary Note 17) In a battery pack including one or more secondary batteries,
A current detection circuit for detecting a current flowing into or out of the secondary battery;
A voltage detection circuit for detecting individual voltages of the secondary battery;
An analog-digital conversion circuit that converts each analog signal output from the current detection circuit and the voltage detection circuit into a digital signal,
A battery pack that outputs the digital signal to the outside.
(Additional remark 18) It further has the temperature detection circuit which detects the temperature of the said secondary battery, The said analog-digital conversion circuit converts the analog signal output from the said temperature detection circuit into a digital signal, and outputs it The battery pack according to appendix 17.
(Additional remark 19) The battery pack of Additional remark 17 or 18 further provided with the memory which stores the input residual amount predicted value and the use condition data of the said secondary battery.
(Supplementary note 20) Any one of Supplementary notes 17 to 19, wherein the analog-to-digital conversion circuit outputs a digital signal obtained by converting an internally generated or externally supplied reference voltage and the analog signal, respectively. Battery pack.
(Supplementary note 21) The battery pack according to any one of supplementary notes 20, wherein the analog-digital conversion circuit simultaneously samples the reference voltage and at least one analog signal.
(Supplementary note 22) The battery pack according to supplementary note 21, wherein the analog-to-digital conversion circuit simultaneously converts the plurality of analog signals sampled simultaneously into digital signals, and sequentially outputs each digital signal.
(Supplementary note 23) The battery pack according to supplementary note 21, wherein the analog-digital conversion circuit sequentially converts the plurality of analog signals sampled and held into digital signals and outputs the digital signals.
(Supplementary Note 24) A semiconductor device in which the analog-digital conversion circuit according to any one of Supplementary Notes 20 to 23 is configured.
(Supplementary Note 25) A semiconductor device provided in a battery pack having one or more secondary batteries,
A current detection circuit for detecting a current flowing into or out of the secondary battery;
A voltage detection circuit for detecting individual voltages of the secondary battery;
An analog-digital conversion circuit that converts each analog signal output from the current detection circuit and the voltage detection circuit into a digital signal;
A semiconductor device comprising:
(Supplementary note 26) The semiconductor according to supplementary note 25, comprising: a switch provided between the secondary battery and a terminal of the battery pack; and a protection circuit for controlling charge / discharge of the secondary battery. apparatus.
(Supplementary note 27) A portable device in which the battery pack according to any one of supplementary notes 17 to 23 is built-in or attachable.

It is a schematic block circuit diagram which shows the portable electronic device which incorporated the battery pack of 1st embodiment. FIG. 2 is a schematic block circuit diagram of the AD conversion circuit of FIG. 1. It is a flowchart explaining an AD conversion system. It is a specific block circuit diagram of an AD conversion circuit. FIG. 3 is a schematic block circuit diagram showing another configuration of FIG. 1. It is a schematic block circuit diagram which shows the portable electronic device incorporating the battery pack of 2nd embodiment. It is explanatory drawing which shows a charge characteristic. It is explanatory drawing which shows the relationship between a charging voltage and discharge capacity. It is a schematic block circuit diagram which shows the portable electronic device incorporating the battery pack of 3rd embodiment. It is a schematic block diagram which shows the example of a conventional structure with respect to FIG. It is a schematic block circuit diagram which shows the general structure of the portable electronic device incorporating a battery pack. It is explanatory drawing which shows the discharge characteristic with respect to the frequency | count of use of a secondary battery. It is explanatory drawing which shows the cycle life characteristic of a secondary battery. It is explanatory drawing which shows the deterioration characteristic of the secondary battery by use environment. It is explanatory drawing which shows the relationship between the discharge electric power with respect to use temperature, and a dischargeable capacity | capacitance. It is a schematic block circuit diagram which shows the 1st prior art structural example provided with the residual amount prediction function. It is a schematic block circuit diagram which shows the 2nd prior art structural example provided with the residual amount prediction function.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 62, 72 Portable apparatus 12, 61, 71 Battery pack 14a-14c Secondary battery 20 Measuring circuit as a measuring means 21 Power supply microcomputer as a data processing means

Claims (7)

In a battery pack comprising a secondary battery,
A current detection circuit for detecting a current flowing into or out of the secondary battery;
A voltage detection circuit for detecting individual voltages of the secondary battery;
An analog-digital conversion circuit that converts each analog signal output from the current detection circuit and the voltage detection circuit into a digital signal,
The digital-to-digital conversion circuit simultaneously samples an internally generated or externally supplied reference voltage and at least one analog signal, and outputs a digital signal obtained by converting the reference voltage and the analog signal, respectively. Battery pack featuring.   2. The battery pack according to claim 1, wherein the analog-digital conversion circuit simultaneously converts the analog signals sampled simultaneously into a digital signal and sequentially outputs the digital signals.   The battery pack according to claim 1, wherein the analog-digital conversion circuit sequentially converts the analog signals sampled simultaneously into digital signals and outputs the digital signals.   The battery pack according to any one of claims 1 to 3, wherein the digital signal is output to the outside. A semiconductor device provided in a battery pack having a secondary battery,
A current detection circuit for detecting a current flowing into or out of the secondary battery;
A voltage detection circuit for detecting a voltage of the secondary battery;
An analog-digital conversion circuit that converts each analog signal output from the current detection circuit and the voltage detection circuit into a digital signal;
With
The analog-digital conversion circuit simultaneously samples a reference voltage generated internally or supplied from the outside and at least one analog signal, and outputs a digital signal obtained by converting the reference voltage and the analog signal, respectively. A featured semiconductor device.   6. The semiconductor device according to claim 5, further comprising: a switch provided between the secondary battery and a terminal of the battery pack; and a protection circuit that controls charging / discharging of the secondary battery.   A portable device in which the battery pack according to any one of claims 1 to 4 is built-in or attachable.

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